Housing Case, Method for Manufacturing Housing Case, and Glass Insert Molding Die Used in Same

ABSTRACT

A housing case ( 1 ) for a small electric device and communication device includes a flat plate ( 2 ) having a dimension substantially the same as that of the front portion of the housing case and comprising at least a glass plate, and a resin frame ( 3 ) integrated with the flat plate ( 2 ) to support the backside periphery of the flat plate ( 2 ).

CROSS REFERENCE TO RELATED APPLICATION

This application is a division of U.S. patent application Ser. No.12/441,635 filed Sep. 20, 2007 which is incorporated herein by referencein its entirety.

TECHNICAL FIELD

The present invention relates to a housing case for a small electricdevice and communication device, the front portion of the housing case;in particular, the portion of the housing case that covers an LCD or anyother display screen having been adequately hardened, and also relatesto a method for manufacturing the housing case and a glass insertmolding die used in the same.

BACKGROUND ART

Small electric devices and communication devices, such as a digitalaudio player and a mobile phone, which can be placed in clothing or in abag and carried, are often subject to impact on their surfaces when theyare accidentally dropped or hit with other articles in the bag.

To address the problem, the housing case of such a device needs to havea highly robust hard coat layer coated on the front portion of thehousing case; in particular, the portion that covers an LCD or any otherdisplay screen, in order to enhance scratch resistance. For example,Patent Document 1 discloses a housing case 100 (see FIG. 38)manufactured from a continuous film having a peelable layer, a hard coatlayer 103, a printed layer, and an adhesive layer successively stackedon a base film. The hard coat layer 103 comprises layered hard coats forhardening the front portion of the housing case 100, and the printedlayer includes a plurality of printed patterns, each of which having anon-printed portion 102. The housing case 100 is manufactured bycontinuously passing the continuous film through a glass insert moldingdie, injecting a transparent synthetic resin onto the adhesive layer ofthe continuous film in the glass insert molding die, and drawing thecontinuous film into the shape of the cavity of the glass insert moldingdie so as to form a synthetic resin layer 101. After the synthetic resinlayer has hardened, the hard coat layer 103, the printed layer, theadhesive layer, and the synthetic resin layer 101 are removed from thebase film and the peelable layer. In FIG. 38, reference numeral 104denotes a display window that covers an LCD display screen, andreference numeral 105 denotes a button hole.

The hard coat layer 103 is typically manufactured by forming a thincoated film, ranging from approximately 3 to 10 μm in thickness, made ofa thermoset resin, a UV curable resin, or any other suitable activeenergy radiation polymerizable resin on a plastic substrate directly orwith an interposed primer layer having a thickness ranging from 0.03 to0.5 μm.

The hard coat layer 103 comprising a thin coated film, however, is nothard enough as the front portion of the housing case; in particular, theportion that covers an LCD or any other display screen where highhardness is required.

The invention has therefore been contrived in view of the above problem.An object of the invention is to provide a housing case, the frontportion of the housing case; in particular, the portion of the housingcase that covers an LCD or any other display screen, being adequatelyhardened. Other objects of the invention are to provide a method formanufacturing the housing case and a glass insert molding die used inthe same.

-   [Patent Document 1] Japanese Laid-open Patent Application No.    2001-36258

DISCLOSURE OF THE INVENTION

To achieve the above objects, a housing case according to the inventionis characterized in that the housing case is used for a small electricdevice or communication device, and comprises a flat plate having adimension substantially the same as that of a front portion of thehousing case and comprising at least a glass plate; and a resin frameintegrated with the flat plate to support a backside periphery of theflat plate.

In the housing case, the flat plate preferably has decoration on a rearsurface of the glass plate.

In the housing case, the device preferably includes a display device,and the flat plate preferably has decoration on the front surface and/orthe rear surface of the glass plate except at least a display window forthe display device.

In the housing case, the rear surface of the glass plate is preferablynot decorated, and the rear surface of the glass plate is preferablyintegrated with the resin frame with an adhesive layer for glass, aprimer layer, and an adhesive layer for resin interposed between therear surface of the glass plate and the resin frame.

In the housing case, the rear surface of the glass plate is preferablydecorated, and the layer having the decoration also preferably serves asan adhesive layer for glass in the portion where the rear surface of theflat plate is integrated with the resin frame. The rear surface of theflat plate is preferably integrated with the resin frame with a primerlayer and an adhesive layer for resin interposed between the rearsurface of the flat plate and the resin frame.

In the housing case, the flat plate preferably has an opening.

The housing case preferably further comprises an opening resin frameintegrated with the flat plate to support the surrounding portion of theopening.

In the housing case, the resin frame preferably covers a side surface ofthe flat plate.

In the housing case, the integrated flat plate and resin framepreferably has a box shape.

In the housing case, the resin frame preferably supports an entirebackside periphery of the flat plate.

In the housing case, the resin frame preferably supports one, two, orthree sides of the backside periphery of the flat plate.

In the housing case, a plurality of divided portions of the resin framepreferably support the backside periphery of the flat plate.

In the housing case, the resin frame is preferably made of a resinmaterial having a molding shrinkage rate of 0.6% or lower.

To achieve the above objects, a glass insert molding die used to form ahousing case according to the invention is characterized in that theglass insert molding die comprises a stationary die and a movable diethat sandwich a flat plate primarily comprised of a glass plate when thedies are closed and form a cavity that faces periphery of the flat platefacing the stationary die and also an end surface of the flat plate. Theglass insert molding die is also characterized in that the stationarydie includes a sliding core having a bottom portion that comes intocontact with the periphery of the flat plate facing the stationary dieand a wall portion that is connected to the bottom portion andpositionably comes into contact with the end surface of the flat plate,the bottom portion and the wall portion provided at the front end of thesliding core; and a suction hole provided in the surface where the flatplate is sandwiched. The glass insert molding die is also characterizedin that the sliding core can be advanced and retracted in thedie-closing direction between a flat plate positioning position and acavity forming position, the flat plate positioning position being theposition where the front-end bottom portion does not protrude from thesurface of the stationary die where the flat plate is sandwiched but thefront-end wall portion comes into contact with the flat plate, and thecavity forming position being the position where the front-end bottomportion and the front-end wall portion are separated from the flatplate.

In the glass insert molding die, it is preferable that the sliding coreis partially provided along the entire perimeter of the flat plate.

In the glass insert molding die, it is preferable that the sliding coreis further capable of being advanced to a glass insert mold pushingposition where the front-end bottom portion protrudes from the surfaceof the stationary die where the flat plate is sandwiched.

To achieve the above objects, a method for manufacturing a housing caseusing the glass insert molding die according to the invention ischaracterized in that the method comprises the steps of: using the glassinsert molding die, moving the sliding core to the flat platepositioning position and then placing the flat plate on the surface ofthe stationary die where the flat plate is sandwiched; suctioning andsecuring the positioned flat plate on the surface where the flat plateis sandwiched; closing the stationary die to which the flat plate hasadhered and the movable die; and after the dies are closed, moving thesliding core to the cavity forming position and then injecting a moltenresin into the cavity to integrate a resin frame with the flat plate.

To achieve the above objects, a method for manufacturing a housing caseusing the glass insert molding die according to the invention ischaracterized in that the method comprises the steps of: using the glassinsert molding die including the pushing mechanism, moving the slidingcore to the flat plate positioning position, and then placing the flatplate on the surface of the stationary die where the flat plate issandwiched; suctioning and securing the positioned flat plate on thesurface where the flat plate is sandwiched; closing the stationary dieto which the flat plate has adhered and the movable die; after the diesare closed, moving the sliding core to the cavity forming position andthen injecting a molten resin into the cavity to integrate a resin framewith the flat plate; and opening the dies and then moving the slidingcore to the glass insert mold pushing position.

In the method for manufacturing a housing case, the flat platepreferably has decoration on the glass plate.

In the method for manufacturing a housing case, the flat platepreferably has an adhesive layer for glass, a primer layer, and anadhesive layer for resin sequentially formed on the glass plate.

In the method for manufacturing a housing case, the portion where theflat plate is sandwiched between the stationary die and the movable diepreferably has an opening.

In the method for manufacturing a housing case, the material of themolten resin preferably has a molding shrinkage rate of 0.6% or lower.

The configuration of the invention described above provides thefollowing advantages:

Since the housing case of the invention includes a flat plate comprisinga glass plate and a resin frame integrated with the flat plate tosupport the backside periphery of the flat plate, the front portion ofthe housing case; in particular, the portion that covers an LCD or anyother display screen, can be adequately hardened.

Since the glass insert molding die and the method for manufacturing ahousing case of the invention can provide a housing case in which aresin frame is integrated with a flat plate primarily comprising a glassplate to support the backside periphery thereof, the front portion ofthe housing case; in particular, the portion that covers an LCD or anyother display screen, can be adequately hardened. Further, since thesliding core provided in the glass insert molding die not only forms acavity for molding the resin frame for supporting the backside peripherybut also serves as a mechanism for positioning the flat plate as well asa mechanism for pushing the glass insert mold as required, the housingcase can be manufactured at a low cost.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an embodiment of a housing caseaccording to the invention;

FIG. 2 is a cross-sectional view of the housing case taken along theline II-II shown in FIG. 1;

FIG. 3 is a cross-sectional view showing another embodiment of thehousing case according to the invention;

FIG. 4 is a cross-sectional view showing another embodiment of thehousing case according to the invention;

FIG. 5 is a cross-sectional view showing another embodiment of thehousing case according to the invention;

FIG. 6 is a cross-sectional view showing another embodiment of thehousing case according to the invention;

FIG. 7 is a rear view showing an embodiment of the housing caseaccording to the invention;

FIG. 8 is a rear view showing another embodiment of the housing caseaccording to the invention;

FIG. 9 is a rear view showing another embodiment of the housing caseaccording to the invention;

FIG. 10 is a rear view showing another embodiment of the housing caseaccording to the invention;

FIG. 11 is a rear view showing another embodiment of the housing caseaccording to the invention;

FIG. 12 is a rear view showing another embodiment of the housing caseaccording to the invention;

FIG. 13 is a perspective view showing another embodiment of the housingcase according to the invention;

FIG. 14 is an enlarged cross-sectional view showing an embodiment of thestructure of a flat plate of the housing case according to theinvention;

FIG. 15 is an enlarged cross-sectional view showing another embodimentof the structure of the flat plate of the housing case according to theinvention;

FIG. 16 is a perspective view showing another embodiment of the housingcase according to the invention;

FIG. 17 is a perspective view showing another embodiment of the housingcase according to the invention;

FIG. 18 shows an embodiment of a stationary die of a glass insertmolding die according to the invention, the stationary die viewed from amovable die side;

FIG. 19 is a cross-sectional view of the stationary die taken along theline XIX-XIX shown in FIG. 18;

FIG. 20 shows the arrangement in which the flat plate is placed in thestationary die, the arrangement viewed from the movable die side;

FIG. 21 is a cross-sectional view of the stationary die taken along theline XXI-XXI shown in FIG. 20;

FIG. 22 is a cross-sectional view showing an embodiment of a step ofmanufacturing the housing case according to the invention;

FIG. 23 is a cross-sectional view showing an embodiment of a step ofmanufacturing the housing case according to the invention;

FIG. 24 is a cross-sectional view showing an embodiment of a step ofmanufacturing the housing case according to the invention;

FIG. 25 is a cross-sectional view showing an embodiment of a stepmanufacturing of the housing case according to the invention;

FIG. 26 shows an example of the housing case obtained by using thestationary die shown in FIG. 18;

FIG. 27 shows another embodiment of the stationary die of the glassinsert molding die according to the invention, the stationary die viewedfrom the movable die side;

FIG. 28 shows another embodiment of the stationary die of the glassinsert molding die according to the invention, the stationary die viewedfrom the movable die side;

FIG. 29 shows an example of the housing case obtained by using thestationary die shown in FIG. 27;

FIG. 30 shows an example of the housing case obtained by using thestationary die shown in FIG. 28;

FIG. 31 shows another embodiment of the stationary die of the glassinsert molding die according to the invention, the stationary die viewedfrom the movable die side;

FIG. 32 is a cross-sectional view of the stationary die taken along theline XXXII-XXXII shown in FIG. 31;

FIG. 33 shows an example of the housing case obtained by using thestationary die shown in FIG. 31;

FIG. 34 is a cross-sectional view showing another embodiment of thestationary die of the glass insert molding die according to theinvention;

FIG. 35 shows another example of the housing case obtained by using thestationary die shown in FIG. 18;

FIG. 36 shows an embodiment of the glass insert molding die according tothe invention in which a transfer film is sandwiched between thestationary die to which the flat plate has adhered and the movable die;

FIG. 37 shows an example of the closed glass insert molding die shown inFIG. 36 after the transfer film is sandwiched;

FIG. 38 is a perspective view showing a housing case of related art; and

FIG. 39 is a cross-sectional view showing how molding shrinkage occurswhen a glass plate, instead of a film comprising a hard coat layer, isinserted into a die and the glass plate is integrated with the wholefront portion of a housing case.

BEST MODE FOR CARRYING OUT THE INVENTION 1. Housing Case

Embodiments of the invention will be described below in detail withreference to the drawings.

A housing case 1 shown in FIG. 1 includes a flat plate 2 having adimension substantially the same as that of the front portion of thehousing case and comprising at least a glass plate, and a resin frame 3integrated with the flat plate 2 to support the backside periphery ofthe flat plate. The portion (b) in FIG. 1 is an exploded view of theportion (a). The housing case 1 is integrated with a back case (notshown), and the resultant integrated case houses a substrate on which avariety of electronic components are mounted to form a small electricdevice or communication device.

The flat plate 2 comprises at least a glass plate, which can providesufficient hardness (at least 9H) of the front portion of the housingcase 1. The glass plate can be any of a standard plate glass, areinforced plate glass, a polished plate glass, and other suitable plateglass. The thickness of the glass plate, in consideration of thestrength, preferably ranges from 0.3 mm to 2.0 mm, more preferably from0.5 mm to 2.0 mm, still more preferably from 0.8 mm to 1.5 mm.

To solve the problem described above, the inventor first planned, in thehousing case of the related art, to integrate the synthetic resin layerwith the flat plate 2 instead of the hard coat 103 in the front portionof the case. Specifically, the whole flat plate 2 is in contact with thesynthetic resin layer 101 in the front portion of the case. Thesynthetic resin layer 101 that has been formed in the injection moldingdie, however, experiences molding shrinkage during coolingsolidification, whereas the portion in contact with the whole flat plate2 does not experience molding shrinkage, as shown in FIG. 39. Since onlyone side thus experiences the molding shrinkage (in the directionindicated by the arrows in FIG. 39, for example), the resultant housingcase 106 is warped in some cases. In this case, the flat plate 2 breakswhen it cannot withstand the warping.

Accordingly, in the invention, the resin frame 3 is employed so thatonly the periphery of the backside of the flat plate 2 is integrated.For example, in FIG. 1, the resin frame 3 supports the entire backsideperiphery of the flat plate 2. Since the resin frame 3 of the inventionis not in contact with the whole flat plate 2, molding shrinkage of theresin frame 3, if any during the cooling solidification, will likely notaffect the whole flat plate 2. The resultant housing case will thereforenot be warped.

The resin frame 3 may be made of a polystyrene resin, a polyolefinresin, an ABS resin, an AS resin, an AN resin, or any other suitablegeneral-purpose resin. Other useable materials may be a polyphenyleneoxide/polystyrene resin, a polycarbonate resin, a polyacetal resin, apolyacrylic resin, a polycarbonate/denatured polyphenylene ether resin,a polybutylene terephthalate resin, an ultrahigh-molecular-weightpolyethylene resin, and any other general-purpose engineering resin; anda polysulfone resin, a polyphenylene sulfide resin, a polyphenyleneoxide resin, a polyallylate resin, a polyether-imide resin, a polyimideresin, a liquid crystal polyester resin, a polyallyl heat-resistantresin, and any other suitable super-engineering resin. In particular, aresin material having a molding shrinkage rate of 0.6% or lower is morepreferably used for the resin frame 3 from the viewpoint of warpingprevention, and an example of such a resin material is a polyacrylicresin. The resin frame 3 may or may not be colored.

The flat plate 2 is integrated with the resin frame 3 in the followingmanner. First, the flat plate 2 is introduced into a molding diecomprising a movable die and a stationary die, and secured in apredetermined position on the cavity surface, for example, throughvacuum suction. After the molding die is closed, a molten resin isinjected through a gate into the cavity to fill it. The resin frame 3 isformed and at the same time bonded to the flat plate 2. After the resinframe 3 is cooled, the molding die is opened and the integrated flatplate 2 and resin frame 3 is removed. When a vertical molding die, whichopens vertically, is used, the flat plate 2 can be secured without usingvacuum suction or other methods.

The integrated flat plate 2 and resin frame 3 may have a box shape (seeFIGS. 2 to 4) or a lid shape (see FIGS. 5 and 6: The broken linerepresents a counterpart back case). FIG. 2 is a cross-sectional viewtaken along the line shown in FIG. 1, and FIGS. 3 to 6 show otherembodiments of that shown in FIG. 2. In either case, the box shape orthe lid shape, setting the dimension of the flat plate 2 to be slightlysmaller than that of the front portion of the housing case 1 as shown inFIGS. 2, 5, and 6 provides more degrees of freedom in designing theexterior appearance of the housing case 1 than a case where thedimension of the flat plate 2 is the same as that of the front portionof the housing case 1 as shown in FIGS. 3 and 4. For example, it ispossible to design the housing case 1 in such a way that the cornersthereof are rounded (see FIGS. 2, 5, and 6). When a box shape isemployed, setting the width of the portion where the flat plate 2 isintegrated with resin frame 3 to be greater than the thickness of thesidewall of the box as shown in FIGS. 2 and 3 increases the area thatsupports the flat plate 2 accordingly, whereby the housing case 1 ismore strengthened.

Roughening the backside periphery of the flat plate 2 allows the flatplate 2 to more intimately adhere to the resin frame 3.

The configuration of the housing case 1 of the invention is not limitedto the aspect described above. For example, the resin frame 3 maysupport one, two, or three sides of the backside periphery (see FIGS. 7to 10), or a plurality of divided portions of the resin frame 3 maysupport the backside periphery of the flat plate 2 (see FIGS. 11 and12). In these cases, molding shrinkage of the resin frame 3, if anyduring the cooling solidification, will likely not affect the whole flatplate 2. Specifically, the housing case will less likely warp than thecase where the resin frame 3 supports the entire backside periphery ofthe flat plate 2. Further, when the resin frame 3 does not support theentire backside periphery of the flat plate 2, input/output terminalsand other components are readily provided on a side surface of thehousing case 1.

The flat plate 2 may have decoration on the backside of the glass plate(not shown). Since the glass plate has a sufficient hardness (at least9H), it is unlikely scratched, and the decoration on the backside viewedthrough the glass plate will not be degraded in terms of aesthetics.

The decoration on the backside of the glass plate is preferably formedby printing a decoration layer. Preferred examples of the material ofthe decoration layer include a polyvinyl chloride resin, a polyamideresin, a polyester resin, a polyacrylic resin, a polyurethane resin, apolyvinyl acetal resin, a polyester urethane resin, a cellulose esterresin, and an alkyd resin, any of which is used as a binder along with acoloring ink containing a pigment or a dye having an appropriate coloras a coloring agent. A preferred example of the printing method isscreen printing. For a solid single color, a variety of coating methods,such as spray coating, can be used.

The decoration layer may alternatively comprise a metal thin film layeror a combination of a printed layer and a metal thin film layer. Themetal thin film layer serves to exhibit metallic luster as thedecoration layer and is formed by using vacuum deposition, sputtering,ion plating, plating, or any other suitable method. In this case,aluminum, nickel, gold, platinum, chromium, iron, copper, tin, indium,silver, titanium, lead, zinc, or any other suitable metal, or any of thealloys or compounds thereof is used in accordance with the metallicluster color to be exhibited. To form a partial metal thin film layer,for example, after a solvent-soluble resin layer is formed on theportion where no metal thin film layer is required, a metal thin film isformed over the surface, and the solvent-soluble resin layer and theunnecessary metal thin film thereon are removed by solvent cleaning. Thesolvent used in this process is water or an aqueous solution in manycases. Alternatively, a metal thin film is formed over the surface, anda resist layer is formed on the portion where the metal thin film needsto be left. Acid or alkali is used to etch away the resist layer.

When the housing case 1 is used for a device including a display device,the flat plate 2 may have decoration on the front surface and/or therear surface of the glass plate except at least a display window for thedisplay device (see FIG. 13). In FIG. 13, the portion (b) is an explodedview of the portion (a), and reference characters 2A and 2B denote adecorated portion and an undecorated portion, respectively. When thefront surface of the glass plate is decorated, the display screen of thedisplay device viewed through the glass plate in the undecorated portion2B will not be degraded in terms of clarity, because the glass plate hassuch a sufficient hardness (at least 9H) that it is unlikely to bescratched. When the rear surface of the glass plate is decorated, notonly will the display screen not be degraded in terms of clarity as inthe case where the front surface of the glass plate is decorated,because the glass plate has such a sufficient hardness (at least 9H)that it is unlikely to be scratched, but also the decoration on the rearsurface viewed through the glass plate in the decorated portion 2A willnot be degraded in terms of aesthetics.

The flat plate 2 of the housing case 1 of the invention may include alayer that allows the flat plate 2 to adhere more intimately to theresin frame 3. For example, an undecorated rear surface of a glass plate2E may be integrated with the resin frame 3 with an adhesive layer forglass 2F, a primer layer 2G, and an adhesive layer for resin 2Hinterposed between the rear surface of the glass plate 2E and the resinframe 3 (see FIG. 14). FIG. 14 is an enlarged cross-sectional view ofthe flat plate 2, and reference character 2D in FIG. 14 denotes a frontsurface decoration layer.

The adhesive layer for glass 2F may be made of a known adhesive forglass, which can be, for example, an adhesive for glass made of apolyester resin.

The primer layer 2G may be made of a known primer material, which canbe, for example, a primer material made of a polyester resin. When theadhesive layer for glass 2F strongly adheres to the adhesive layer forresin 2H, the primer layer 2G can be omitted.

The adhesive layer for resin 2H may be made of a known adhesive forresin, which can be, for example, an adhesive for resin made of a vinylchloride/vinyl acetate/acrylic resin.

The flat plate 2 of the housing case 1 of the invention mayalternatively include the layer described below that allows the flatplate 2 to adhere more intimately to the resin frame 3. Specifically,the rear surface of the glass plate 2E is decorated, and the layercontaining the decoration also serves as an adhesive layer for glass inthe portion where the rear surface of the flat plate 2 is integratedwith the resin frame 3. The rear surface of the flat plate 2 can beintegrated with the resin frame 3 with the primer layer 2G and theadhesive layer for resin 2H interposed between the rear surface of theflat plate 2 and the resin frame 3 (see FIG. 15). FIG. 15 is an enlargedcross-sectional view of the flat plate 2. Reference character 2I in FIG.15 denotes the backside decoration layer, which also serves as theadhesive layer for glass in the integrated portion. The decorativelayer/adhesive layer for glass can be made of the same material as thatof the adhesive layer for glass 2F described above but containing apigment or a dye having an appropriate color as a coloring agent. Inthis case, the glass plate is unlikely to be scratched because it has asufficient hardness (at least 9 H), whereby the decoration on the rearsurface viewed through the glass plate will not be degraded in terms ofaesthetics.

The adhesive layer for glass 2F, the primer layer 2G, the adhesive layerfor resin 2H, and the decorative layer/adhesive layer for glass may beformed, for example, by screen printing.

The flat plate 2 of the housing case 1 of the invention may have anopening 2C (see FIG. 16). The housing case 1 shown in FIG. 16 isintegrated with a back case (not shown), and the resultant integratedcase houses a substrate on which a flash memory or other electronicelements, a liquid crystal panel or other display devices, apiezoelectric speaker for outputting an operating sound, a battery, andan operation panel that fits in the opening 2C are mounted. A digitalaudio player is thus formed. The portion (b) in FIG. 16 is an explodedview of the portion (a).

When the flat plate 2 of the housing case 1 of the invention has theopening 2C, it is further preferable to provide an opening resin frame 4integrated with the flat plate 2 to support the surrounding portion ofthe opening 2C, as shown in FIG. 17. The thus configured housing case 1is further strengthened. The opening resin frame 4 can be implemented ina variety of aspects as in the case of the resin frame 3. The portion(b) in FIG. 17 is an exploded view of the portion (a).

When the housing case 1 of the invention is configured in such a waythat the resin frame 3 covers the side surfaces of the flat plate 2 notto create any step as shown in FIGS. 2, 5, and 6, there is no risk thatthe flat plate 2 is peeled off the resin frame 3 when any of the sidesurfaces of the flat plate 2 is caught by something when the product isin use.

2. Glass Insert Molding Die and Method for Manufacturing Housing Case

A glass insert molding die and a method for manufacturing the housingcase will now be described. First, the housing case 1 provided in thepresent embodiment will be described with reference to FIGS. 26, 29, 30,33, and 35. Any of the housing cases 1 shown in FIGS. 26, 29, 30, 33,and 35 includes the flat plate 2, which takes up almost all the frontarea of the housing case and comprises at least a glass plate, and theresin frame 3, which supports the backside periphery of the flat plate 2and is integrated with the flat plate 2 in such a way that the resinframe 3 covers at least the portion of the end surfaces of the flatplate 2 that is connected to the supported portion. In FIGS. 26, 29, 30,33, and 35, the portion (a) is a front view; the portion (b) is a rearview; and the portions (c) and (d) are cross-sectional views. Thehousing case 1 is integrated with a back case (not shown), and theresultant integrated case houses a substrate on which a variety ofelectronic components are mounted. A small electric device orcommunication device is thus formed.

In the invention, the resin frame 3, which is integrated with theperiphery of the rear surface of the flat plate 2, is insert-molded. Forexample, in FIGS. 26, 33, and 35, the resin frame 3 supports all thebackside periphery of the flat plate 2, whereas in FIGS. 29 and 30, theresin frame 3 supports a substantially C-shaped portion obtained bycutting part of the backside periphery of the flat plate 2. Since theresin frame 3 of the invention is not in contact with the whole flatplate 2, molding shrinkage of the resin frame 3, if any during thecooling solidification, will likely not affect the whole flat plate 2.The resultant housing case will therefore not suffer from warping.

Further, in the invention, since the resin frame 3 covers the endsurfaces of the flat plate 2, there is no risk of the flat plate 2peeling off the resin frame 3 when any of the end surfaces of the flatplate 2 is caught by something when the product is in use.

The flat plate 2 is integrated with the resin frame 3 by using a glassinsert molding die, which will be described below.

The glass insert molding die includes a stationary die 15 and a movabledie 10 that sandwich the flat plate 2 primarily comprising a glass platewhen the dies are closed and form a cavity that faces not only theperiphery of the flat plate 2 facing the stationary die 15 but also theend surfaces of the flat plate 2. The stationary die 15 includes asliding core 5 having a bottom portion that comes into contact with theperiphery of the flat plate 2 facing the stationary die 15 (hereinafterreferred to as a front-end bottom portion 5 b) and a wall portion thatis connected to the front-end bottom portion 5 b and positionally comesinto contact with the end surfaces of the flat plate 2 (hereinafterreferred to as a front-end wall portion 5 a). The front-end wall portion5 a and the front-end bottom portion 5 b are provided at the front endof the sliding core 5. The stationary die 15 further includes suctionholes 8 provided in the surface where the flat plate 2 is sandwiched(hereinafter referred to as a flat plate abutting surface 7) (see FIGS.18 and 19). FIG. 19 is a cross-sectional view taken along the lineXIX-XIX shown in FIG. 18.

The sliding core 5 is capable of being advanced and retracted using adrive unit (not shown) in the direction in which the dies are closedbetween a flat plate positioning position I and a cavity formingposition II. The flat plate positioning position I is the position wherethe front-end bottom portion 5 b does not protrude from the surface ofthe stationary die 15 where the flat plate 2 is sandwiched but thefront-end wall portion 5 b comes into contact with the flat plate 2 (seeFIGS. 19, 21 and 22). The cavity forming position II is the positionwhere the front-end bottom portion 5 b and the front-end wall portion 5a are separated from the flat plate 2 (see FIGS. 23 and 24). The slidingcore 5 is capable of being advanced to a glass insert mold pushingposition III where the front-end bottom portion 5 b protrudes from theflat plate abutting surface 7 of the stationary die 15 as required (seeFIG. 25).

In FIGS. 19, 21, and 22, the front-end bottom portion 5 b of the slidingcore 5 is seamlessly connected with the flat plate abutting surface 7 ofthe stationary die 15. A groove 14 may alternatively be formed betweenthe front-end bottom portion 5 b and the flat plate abutting surface 7(see FIG. 34). In this case, the area of the resin frame 3 that isintegrated with the backside periphery of the flat plate 2 increases bythe amount of the resin that fills the groove 14 in the molding process.The flat plate positioning position I may be set in such a way that thefront-end bottom portion 5 b is flush with the flat plate abuttingsurface 7 of the stationary die 15 as shown in FIGS. 19, 21, and 22. Theflat plate positioning position I may alternatively be set in such a waythat the front-end bottom portion 5 b is retracted from the flat plateabutting surface 7 of the stationary die 15, because the flat plate 2can be positioned as long as the front-end wall portion 5 a comes intocontact with the end surfaces of the flat plate 2.

The front-end wall portion 5 a to positionally come into contact withthe end surfaces of the flat plate 2 can be formed into two U-shapedportions facing each other when viewed in the direction perpendicular toa die parting plane 6, for example, as shown in FIG. 18. The arrangementof the front-end wall portion 5 a is, of course, not limited to theaspect described above, but the arrangement may be determined asappropriate not to misalign the flat plate 2 in accordance with theshape of the flat plate 2. For example, the front-end wall portion 5 acan be disposed at each corner of the flat plate 2 or at part of eachside of the flat plate 2. The flat plate 2 can have an arbitrary shape,such as a rectangle with rounded corners as shown in FIG. 18, arectangle with square corners, and an ellipse. Further, the number ofsliding cores 5 is not limited to a specific number. Moreover, thesliding core 5 may be partially provided along the perimeter of the flatplate 2 as shown in FIG. 18, or the front-end wall portion 5 a maycompletely surround the flat plate 2.

A method for manufacturing the housing case 1 using the thus configuredglass insert molding die will now be described.

First, after the sliding core 5 is moved to the flat plate positioningposition I, the flat plate 2 is placed on the flat plate abuttingsurface 7 of the stationary die 15 (see FIGS. 20 and 21). FIG. 21 is across-sectional view taken along the line XXI-XXI shown in FIG. 20.

In this positioned state, the flat plate 2 is suctioned and secured onthe flat plate abutting surface 7 as a result of air 12 being suctionedthrough the suction holes 8 provided in the flat plate abutting surface7 (see FIG. 22). The process by which the flat plate is suctioned andsecured is not necessarily limited to the suctioning of air. Forexample, suction cups may be provided on the surface where the flatplate 2 is sandwiched.

The movable die 10 is then advanced toward the stationary die 15 towhich the flat plate 2 has adhered so as to close the dies, whereby themovable die 10 and the flat plate abutting surface 7 of the stationarydie 15 sandwich the flat plate 2, and the stationary die 15, the movabledie 10, and the flat plate 2 form a cavity 13, which is a die space (seeFIG. 23). At this point, the drive unit (not shown) retracts the slidingcore 5 to the position where the front-end bottom portion 5 b isseparated by a predetermined distance from the backside periphery of theflat plate 2, and a molten resin can now reach the portion that was incontact with the front-end wall portion 5 a and the front-end bottomportion 5 b of the sliding core 5 (cavity forming position II). Theretraction of the sliding core 5 may be carried out at any of thefollowing points in time immediately before the movable die 10 startsbeing advanced, during the forward movement, and immediately after theadvancing movement is completed.

After the sliding core 5 is moved to the cavity forming position II andthe cavity 13 is filled with the molten resin injected through a gate11, the resin frame 3 is integrated with the flat plate 2 in such a waythat the resin frame 3 supports the backside periphery of the flat plate2 and covers the portion of the end surfaces of the flat plate 2 that isconnected to the supported portion. The housing case 1, which is theglass insert mold, is thus obtained (see FIG. 24).

The molten resin may be a polystyrene resin, a polyolefin resin, an ABSresin, an AS resin, an AN resin, or any other suitable general-purposeresin. Other useable materials may be a polyphenylene oxide/polystyreneresin, a polycarbonate resin, a polyacetal resin, a polyacrylic resin, apolycarbonate/denatured polyphenylene ether resin, a polybutyleneterephthalate resin, an ultrahigh-molecular-weight polyethylene resin,and any other general-purpose engineering resin; and a polysulfoneresin, a polyphenylene sulfide resin, a polyphenylene oxide resin, apolyallylate resin, a polyether-imide resin, a polyimide resin, a liquidcrystal polyester resin, a polyallyl heat-resistant resin, and any othersuitable super-engineering resin. In particular, a resin material havinga molding shrinkage rate of 0.6% or lower is more preferably used forthe resin frame 3 in terms of preventing warping, and an example of sucha resin material is a polyacrylic resin. The resin frame 3 may or maynot be colored.

After the movable die 10 is refracted to be separated from thestationary die 15, specifically, the dies are opened, the drive unitforwards the sliding core 5 to the glass insert mold pushing positionIII (see FIG. 25). In this process, the sliding core 5 serves as anejector pin, and the housing case 1 is smoothly separated from thestationary die 15. The housing case 1 can thus be readily removed fromthe die device. When a dedicated ejector pin is separately prepared, thesliding core 5 is not necessarily used to push the glass insert mold.

As described above, in the method for manufacturing the housing caseusing the glass insert molding die according to the present embodiment,since the sliding core 5 not only forms the cavity for molding the resinframe 3 for supporting the backside periphery but also serves as themechanism for positioning the flat plate 2 as well as the mechanism forpushing the glass insert mold as required, the housing case 1 can bemanufactured at a low cost.

The integrated flat plate 2 and resin frame 3 may have a lid shape (seeFIGS. 26, 29, and 30) or a box shape (see FIGS. 33 and 35). FIGS. 26( c)and 26(d) are cross-sectional views taken along the lines XXVIc-XXVIcand XXVId-XXVId in FIG. 26( b), respectively. FIGS. 29( c) and 29(d) arecross-sectional views taken along the lines XXIXc-XXIXc and XXIXd-XXIXdin FIG. 29( b), respectively. FIGS. 30( c) and 30(d) are cross-sectionalviews taken along the lines XXXc-XXXc and XXXd-XXXd in FIG. 30( b),respectively. Even when the box shape is employed, it is conceivablethat a box sidewall cavity is formed outside the sliding core 5 as shownin FIG. 33, or a sidewall cavity is formed by refracting the slidingcore 5 as shown in FIG. 35. The same notation as that used in the abovecases applies to FIGS. 33 and 35. FIGS. 33( c) and 33(d) arecross-sectional views taken along the lines XXXIIIc-XXXIIIc andXXXIIId-XXXIIId in FIG. 33( b), respectively. FIGS. 35( c) and 35(d) arecross-sectional views taken along the lines XXXVc-XXXVc and XXXVd-XXXVdin FIG. 35( b), respectively.

Among the backside periphery and end surfaces of the flat plate 2, theportions that do not correspond to the sliding core 5 are notnecessarily integrated with the resin frame 3 as shown in FIGS. 26, 33,and 35. For example, only the end surface that does not correspond tothe sliding core 5 may be integrated with the resin frame 3 as shown inFIG. 29, or the backside periphery or end surface that does notcorrespond to the sliding core 5 may not integrated with the resin frame3 as shown in FIG. 30. To obtain the housing case 1 shown in FIG. 29,the flat plate abutting surface 7 in FIG. 18 is extended to the lowerinner wall of a cavity forming portion 9 as shown in FIG. 27 so that thecorresponding portion of the backside periphery of the glass plate 2 isnot filled with the molten resin. To obtain the housing case 1 shown inFIG. 30, the flat plate abutting surface 7 in FIG. 18 is not changed butthe lower inner wall of the cavity forming portion 9 is shifted to thelower end of the flat plate abutting surface 7 as shown in FIG. 28 sothat the corresponding portions of the backside periphery and the endsurface of the glass plate 2 are not filled with the molten resin.

The flat plate 2 may be a decorated glass plate as shown in FIGS. 26,29, 30, 33, and 35, or may be an undecorated, skeleton glass plate. InFIGS. 26, 29, 30, 33, and 35, reference character 2A denotes thedecorated portion, and reference character 2B denotes the undecoratedportion, which becomes a transparent window.

The decoration on the rear surface of the glass plate is formed byprinting a decoration layer. Examples of the material of the decorationlayer may include a polyvinyl chloride resin, a polyamide resin, apolyester resin, a polyacrylic resin, a polyurethane resin, a polyvinylacetal resin, a polyester urethane resin, a cellulose ester resin, andan alkyd resin, any of which is used as a binder along with a coloringink containing a pigment or a dye having an appropriate color as acoloring agent. An example of the printing method may be screenprinting. For a solid single color, a variety of coating methods, suchas spray coating, can be used.

The decoration layer may alternatively comprise a metal thin film layeror a combination of a printed layer and a metal thin film layer. Themetal thin film layer serves to exhibit metallic luster as thedecoration layer and is formed by using vacuum deposition, sputtering,ion plating, plating, or any other suitable method. In this case,aluminum, nickel, gold, platinum, chromium, iron, copper, tin, indium,silver, titanium, lead, zinc, or any other suitable metal, or any of thealloys or compounds thereof is used in accordance with the metallicluster color to be exhibited. To form a partial metal thin film layer,for example, after a solvent-soluble resin layer is formed on theportion where no metal thin film layer is required, a metal thin film isformed over the surface, and the solvent-soluble resin layer and theunnecessary metal thin film thereon are removed by solvent cleaning. Thesolvent used in this process is water or an aqueous solution in manycases. Alternatively, a metal thin film is formed over the surface, anda resist layer is formed on the portion where the metal thin film needsto be left. Acid or alkali is used to etch away the resist layer.

Roughening the surface of the flat plate 2 that is integrated with theresin frame 3 allows the flat plate 2 to more intimately adhere to theresin frame 3.

The glass insert molding die of the invention may include simultaneousmolding/painting means 16 for allowing a transfer film 17 to besandwiched between the stationary die 15 to which the flat plate 2 hasadhered and the movable die 10 (see FIG. 36). After the transfer film 17is sandwiched between the stationary die 15 to which the flat plate 2has adhered and the movable die 10, and the dies are closed (see FIG.37), the painting portion of the transfer film 17 can be transferred tothe resin frame 3 integrated with the flat plate 2 simultaneously withthe injection of the molten resin. Specifically, the glass insertmolding die of the invention also serves as a simultaneousmolding/transferring die.

The transfer film 17 includes a transfer layer on an elongated basesheet. The transfer layer has a peelable layer, a pattern layer, anadhesive layer, and other layers sequentially stacked. The peelablelayer allows the transfer layer to be peeled off the base sheet. Thepattern layer provides the surface of an injection-molded piece withdecorative appearance and functionality. Examples of the pattern layerinclude a typical printed pattern and a conductive pattern made of aconductive material. The adhesive layer bonds the transfer layer to theresin frame 3, which is the molded piece.

The transfer film 17 may be adapted in such a way that a film feedingdevice shown in FIG. 36 feeds the painting portion of the transfer film17 between the dies by a predetermined length at a time. Alternatively,a plurality of transfer film sheets may be fed sheet by sheet.

Any of the variety of embodiments can be combined as appropriate toprovide the respective advantageous effects. While the invention hasbeen adequately described with reference to the accompanying drawings inrelation to preferred embodiments, a variety of variations andmodifications shall be apparent to those skilled in the art. Suchvariations and modifications should be taken as encompassed within thescope of the invention to the extent that they do not depart from thescope of the invention set forth by the claims.

Examples, of the values in the above embodiments will be describedbelow, but the scope of the invention is not limited thereto.

Example 1

A glass plate of 88 mm in length, 38 mm in width, and 1 mm in thicknesswas prepared, and a circular opening for an operation panel was providedin the glass plate. A decorative layer was then formed on one side ofthe glass plate except a display window for a liquid crystal screen byusing screen printing along with an ink containing a coloring agent anda polyester resin as a binder. An adhesive layer for glass made of apolyester resin, a primer layer made of a polyester resin, and anadhesive layer for resin made of a vinyl chloride/vinyl acetate/acrylicresin were then sequentially formed on the entire periphery of theundecorated side of the glass plate by using screen printing. A flatplate was thus obtained.

The flat plate was introduced into a molding die comprising a movabledie and a stationary die, and secured in a predetermined position on thecavity surface through vacuum suction. After the molding die was closed,a molten polyacrylic resin was injected through the gate to fill thecavity. A rectangular resin frame was formed, and at the same time theresin frame was bonded to the undecorated surface of the flat plate withthe adhesive layer for resin, the primer layer, and the adhesive layerfor glass interposed between the resin frame and the undecorated surfaceof the flat plate. After the resin frame was cooled, the molding die wasopened to remove the resin frame integrated with the entire backsideperiphery of the flat plate. A digital audio player housing case of 90mm in length, 40 mm in width, and 4 mm in height with the cornersrounded at a radius R of 1 mm was thus obtained.

Example 2

A glass plate of 88 mm in length, 38 mm in width, and 1 mm in thicknesswas prepared, and a circular opening for an operation panel was providedin the glass plate. A decorative layer/adhesive layer for glass was thenformed on one side of the glass plate except a display window for aliquid crystal screen by using screen printing along with an inkcontaining a coloring agent and a polyester resin as a binder. A primerlayer made of a polyester resin and an adhesive layer for resin made ofa vinyl chloride/vinyl acetate/acrylic resin were then sequentiallyformed on the entire periphery of the decorated side of the glass plateby using screen printing. A flat plate was thus obtained.

The flat plate was introduced into the molding die comprising themovable die and the stationary die, and secured in a predeterminedposition on the cavity surface through vacuum suction. After the moldingdie was closed, a molten polyacrylic resin was injected through the gateto fill the cavity. A rectangular resin frame was formed, and at thesame time the resin frame was bonded to the decorated surface of theflat plate with the adhesive layer for resin and the primer layerinterposed between the resin frame and the decorated surface of the flatplate. After the resin frame was cooled, the molding die was opened toremove the resin frame integrated with the entire backside periphery ofthe flat plate. A digital audio player housing case of 90 mm in length,40 mm in width, and 4 mm in height with the corners rounded at a radiusof 1 mm was thus obtained.

Example 3

Example 3 only differs from Example 1 in that the adhesive layer forglass, the primer layer, and the adhesive layer for resin weresequentially formed on not only the periphery of the glass plate butalso the entire surrounding portion of the opening in the undecoratedsurface of the flat plate to form a flat plate; a rectangular resinframe and a circular opening resin frame were formed by using injectionmolding; and at the same time, the resin frame and the opening resinframe were bonded to the undecorated surface of the flat plate with theadhesive layer for resin, the primer layer, the adhesive layer for glassinterposed between the resin frames and the undecorated surface of theflat plate.

Example 4

Example 4 only differs from Example 2 in that the primer layer and theadhesive layer for resin were sequentially formed on not only theperiphery of the glass plate but also the entire surrounding portion ofthe opening in the decorated surface of the flat plate to form a flatplate; a rectangular resin frame and a circular opening resin frame wereformed by using injection molding; and at the same time, the resin frameand the opening resin frame were bonded to the decorated surface of theflat plate with the adhesive layer for resin and the primer layerinterposed between the resin frames and the decorated surface of theflat plate.

Example 5

Example 5 only differs from Example 3 in that the resin frame is dividedinto two.

Example 6

Example 6 only differs from Example 4 in that each of the resin frameand the opening resin frame is divided into two.

Example 7

A glass plate of 88 mm in length, 38 mm in width, and 1 mm in thicknesswas prepared, and a circular opening for an operation panel was providedin the glass plate. A decoration layer was then formed on one side ofthe glass plate except a display window for a liquid crystal screen byusing screen printing along with an ink containing a coloring agent anda polyester resin as a binder. An adhesive layer for glass made of apolyester resin, a primer layer made of a polyester resin, and anadhesive layer for resin made of a vinyl chloride/vinyl acetate/acrylicresin were then sequentially formed on the entire periphery of theundecorated side of the glass plate by using screen printing. A flatplate was thus obtained.

In this case, the glass insert molding die of the invention describedabove was used. After the sliding core was moved to the flat platepositioning position, the flat plate was placed on the surface of thestationary die where the flat plate was sandwiched, and the positionedflat plate was suctioned by suctioning air through the suction holes andsecured on the surface where the flat plate to be sandwiched. After thestationary die to which the flat plate had adhered and the movable diewere closed, and the sliding core was moved to the cavity formingposition, a molten resin was injected into the cavity to integrate theflat plate with a resin frame. After the die was opened, the slidingcore was moved to the glass insert mold pushing position and the glassinsert mold was removed. A digital audio player housing case of 90 mm inlength, 40 mm in width, and 4 mm in height with the corners rounded at aradius of 1 mm was thus obtained.

Example 8

A glass plate of 88 mm in length, 38 mm in width, and 1 mm in thicknesswas prepared, and a circular opening for an operation panel was providedin the glass plate. A decorative layer/adhesive layer for glass was thenformed on one side of the glass plate except a display window for aliquid crystal screen by using screen printing along with an inkcontaining a coloring agent and a polyester resin as a binder. A primerlayer made of a polyester resin and an adhesive layer for resin made ofa vinyl chloride/vinyl acetate/acrylic resin were then sequentiallyformed on the entire periphery of the decorated side of the glass plateby using screen printing. A flat plate was thus obtained.

The glass insert molding was performed in the same manner as Example 7,and a digital audio player housing case of 90 mm in length, 40 mm inwidth, and 4 mm in height with the corners rounded at a radius of 1 mmwas obtained.

For all the housing cases of Examples 1 to 8, the front portion of thecase, in particular, the portion that covers the display screen, such asan LCD, was adequately hardened.

INDUSTRIAL APPLICABILITY

The invention is preferably applicable to a housing case, for example,for a small electric device and communication device, a method formanufacturing the housing case, and a glass insert molding die used inthe same.

1. A housing case for a small electric device and communication device,the housing case comprising: a flat plate having a dimensionsubstantially the same as that of a front portion of the housing caseand comprising at least a glass plate; and a resin frame integrated withthe flat plate to support a backside periphery of the flat plate.
 2. Thehousing case according to claim 1, wherein the flat plate has decorationon a rear surface of the glass plate.
 3. The housing case according toclaim 1, wherein the device includes a display device; and the flatplate has decoration on the front surface and/or the rear surface of theglass plate except at least a display window for the display device. 4.The housing case according to claim 1, wherein the rear surface of theglass plate is not decorated; and the rear surface of the glass plate isintegrated with the resin frame, with an adhesive layer for glass, aprimer layer, and an adhesive layer for resin interposed between therear surface of the glass plate and the resin frame.
 5. The housing caseaccording to claim 3, wherein the rear surface of the glass plate isdecorated, the layer having the decoration also serves as an adhesivelayer for glass in the portion where the rear surface of the flat plateis integrated with the resin frame; and the rear surface of the flatplate is integrated with the resin frame with a primer layer and anadhesive layer for resin interposed between the rear surface of the flatplate and the resin frame.
 6. The housing case according to claim 1,wherein the flat plate has an opening.
 7. The housing case according toclaim 6, further comprising an opening resin frame integrated with theflat plate to support the surrounding portion of the opening.
 8. Thehousing case according to claim 1, wherein the resin frame covers a sidesurface of the flat plate.
 9. The housing case according to claim 1,wherein the integrated flat plate and resin frame has a box shape. 10.The housing case according to claim 1, wherein the resin frame supportsthe entire backside periphery of the flat plate.
 11. The housing caseaccording to claim 1, wherein the resin frame supports one, two, orthree sides of the backside periphery of the flat plate.
 12. The housingcase according to claim 1, wherein a plurality of divided portions ofthe resin frame support the backside periphery of the flat plate. 13.The housing case according to claim 1, wherein the resin frame is madeof a resin material having a molding shrinkage rate of 0.6% or lower.